Absorbent wabbing



Patented Aug. 15, 1939 UNITED STATES ABSORBENT WADDING, PARTICULARLY FOR SURGICAL PURPOSES Hans Freudenberg, Weinheim, Germany, assignor to Carl Frcudenberg G. m. b. H., Weinheim,

Baden, Germany No Drawing. Application May 15, 1936, Serial No. 80,019. In Germany May 20, 1935 1 Claim.

The invention relates to absorbent wadding, particularly for surgical purposes, which consists of animal collagenous fibres derived from hides or sinews.

It has already been proposed to prepare absorbent tampons for surgical purposes from flesh or muscular tissue by subjecting the same to chemical treatment and mechanical working up in the expectation that absorbent products could. be obtained from the flesh substance.

According to this invention it has been found contrary to expectation that fibres, which'have been obtained from animal hide material, such as hide or sinews, notwithstanding that the character of the hide material differs from the flesh,

may be employed as absorbent wadding, particularly for surgical purposes.

According to this invention the absorbent wadding is prepared by converting hide or sinews by a chemical or thermal swelling process into a condition adapted for the mechanical isolation of the fibres, thereafter effecting coarse shredding of the swollen material in such a way as to preserve the fibres, drying the resulting coarse fibrous material by treatment with organic liquids miscible with Water and thereafter finely shredding the dried material.

Hides, hide Waste or sinews of any kind are employed as starting materials for the preparation of the wadding.

These starting materials may be opened up or disintegrated by treatment with swelling chemicals. The swelling may be effected with alkaline or acid liquids or with salt solutions. If desired various swelling agents may be employed, the concentrations of which are adapted to the nature of the starting material as well as to the degree of desired disintegration.

The disintegration of the hide may also be effected by a heat treatment in the presence of water. Finally the starting materials may be subjected to a partial hydrolytic decomposition under the action of heat and be simultaneously or subsequently treated with swelling chemicals.

The disintegrated hide material is comminuted and coarsely shredded by mechanical treatments, whereby it is important that the fibres should as far as possible not be damaged and in particular that the natural length of the fibres should be retained. The comminuation and coarse shredding may be carried out in one or more stages with the aid of crushing, comminuating and tearing apparatus, for example crushing rollers, Hollanders or opening mills.

The resulting coarse fibrous material, which consists substantially of fibre bundles, is then treated in one or more stages with organic liquids miscible with water, particularly alcohols, preferably ethyl alcohol, or acetone, whereby the water absorbed during the swelling is more or less displaced. It is advisable in this case first to free the coarse fibrous material from the main quantity of aqueous liquid present by procedures such as draining, expressing, centrifuging or the like and only thereafter to treat the material with organic liquids. The quality of the wadding pro duced depends on the degree of water displacement or dehydration. The further the dehydration is forced, the softer the products obtained during the fine shredding operation become. Accordingly the concentration of the organic solvent employed depends on the desired properties of the finished product and in the case of alcohol for example amounts to GOO-100%.

The more or less dried coarse fibrous mass is thereafter subjected to a fine shredding operation by treatment with carding combs or carding machines, whereby the fibre bundles are converted into fine fibres.

It is frequently advisable to subject the wadding in the course of its production to slight tanning and in this Way to obtain products, which on the one hand show an increased resistance to Water and on the other hand still retain their absorbing powers. The slight tanning, which may take place at different stages in the production of the wadding, may be effected, for example, with formaldehyde. The coarsely shredded material may be slightly tanned with substances having a tanning action, such as formaldehyde, thereafter treated with organic solvents, miscible with Water and then finely shredded. The tanning may also be effected by treating the coarse fibrous material with organic solvents containing tanning agents and the tanned material thereafter finely shredded. A further alternative is to treat the fine fibres with formaldehyde, in which event the fibres must be again more or less extensively dried after the treatment, for example by treatment with organic solvents miscible with water.

Depending upon the degree of dehydration the end product constitutes a more or less soft, white and completely absorbent wadding, which may be employed for various, particularly surgical, purposes. The wadding may be impregnated in the usual manner with substances, for example iodine, which may be of use in their application. Furthermore the sterility of the Wadding already produced by treatment with organic solvents may be increased by treatment with sterilising agents, such as iodine or cumene, during the production or subsequently thereto these substances being, for example, introduced during the displacement of water by organic solvents together with the latter. When effecting slight tanning with formaldehyde the latter simultaneously exerts a sterilising effect.

Examples 1. 100 kgms. of hide Waste is immersed for 8 weeks in milk of lime at 18 C. and thereafter coarsely shredded in an opening mill. The resulting coarse fibrous mass is freed from lime with dilute hydrochloric acid and thoroughly washed. The material so obtained is passed through a roller press and the resulting moist fibrous mass, amounting to about kgms, is introduced into a vessel together with 50 liters of 96% alcohol. After 5 hours the alcohol in the fibrous mass is for the greater part separated by expressing and the expressed fibrous mass is again introduced into 50 litres of 96% alcohol. After a further 5 hours the product is expressed, dried in the air and finally conveyed over a carding comb. A pure white, soft, absorbent fibrous mass which completely resembles cotton wool is obtained. If it is desired to increase the sterilising effect produced by the treatment with alcohol, hot alcohol, or the addition of for example 10 gms. of iodine or Rivanol, may be employed for the last immersion.

2. 100 kgms. of hide waste are subjected for 2 weeks to swelling in an 8% sulphurous acid solution and thereafter coarsely shredded as described in Example 1. The resulting very white, bleached and germ-free fibrous mass is immersed for 5 hours in 120 litres of acetone. The mass is thereafter expressed and dried to such an extent that the material still contains about 40% of acetone. In this condition the product is conveyed over a carding comb. A wadding-like prodnot is obtained having somewhat more elastic properties than the product obtained according to Example 1.

3. 100 kgms. of hide waste are chemically pretreated as described in Example 1 and coarsely shredded. The fibrous paste is thereafter stirred with 12 litres of a formaldehyde solution and after standing for 3 hours is expressed at air temperature. The expressed material is treated with ammonium chloride solution until it is practically free from lime and is then again expressed between rollers. The fibrous product is thereafter treated with litres of alcohol and after again expressing dried and carded. A sterile, white and soft fibrous mass results, the swelling power of which is less than that of the product obtained according to Examples 1 and 2.

4. kgms. of sinew material are swollen in a 7% hydrochloric acid solution and thereafter coarsely shredded with the aid of crushing and porcupine rollers. The coarse fibrous material is extensively freed from water with the aid of acetone, to which antiseptic agents may be added, and is brought in this condition on to a carding comb. The carded product constitutes an absorbent wadding very suitable for surgical purposes.

What I claim is:

Wadding consisting of absorbent collagenous fibres substantially free from water, which fibres are produced by converting animal hide material into a swollen condition in which the fibres contained therein may be mechanically isolated, shredding the swollen material while preserving the fibres, treating the resulting coarse fibrous material with organic liquids miscible with water and finely shredding the material so produced.

HANS FREUDENBERG. 

